In a wireless communication system based on the TDD scheme, the same frequency is used for uplink and downlink communication. FIG. 1 is a drawing showing a configuration example of a transmitted/received frame in the TDD scheme. In the TDD scheme, as the transmitted/received frame 101 of a base station A shown in FIG. 1, a frame is utilized for communication while being divided into DL (Downlink) transmission, guard time, and UL (Uplink) reception. Here, the guard time is a time interval provided so as to prevent interference from occurring when DL transmission is switched to UL reception or vice versa. The ratios between DL transmission, guard time, and UL reception within a transmitted/received frame can be adjusted to optimum ratios according to the degree of congestion in the uplink and downlink traffic of each base station.
Patent Literature 1 describes a technology that sets the angle of an antenna so as to decrease interference to adjacent cells in the TDD scheme.
Japanese Patent Kohyo Publication No. JP-P2005-525041A